Methods of recovering rare earth elements

ABSTRACT

Processes described include reacting a fresh or spent catalyst, or sorbent, with a solution containing an extracting agent (such as an acid or a base). Preferably, the catalyst contains both alumina and a molecular sieve (or a sorbent), and the reaction is performed under relatively mild conditions such that the majority of the base material does not dissolve into the solution. Thus, the catalyst can be re-used, and in certain instances the catalyst performance even improves, with or without re-incorporating certain of the metals back into the catalyst. Additionally, metals contained in the catalyst, such as Na, Mg, Al, P, S, Cl, K, Ca, V, Fe, Ni, Cu, Zn, Sr, Zn Sb, Ba, La, Ce, Pr, Nd, Pb, or their equivalent oxides, can be removed from the catalyst. Some of the metals that are removed are relatively valuable (such as the rare earth elements of La, Ce, Pr and Nd).

This application is a divisional of application Ser. No. 13/163,325,filed Jun. 17, 2011.

The present invention relates generally to methods of recovering rareearth elements from a rare earth containing material and/or to methodsof producing a solution containing one or more rare earth elements thathave been extracted from rare earth containing material. Moreparticularly, the present invention relates to the application of suchmethods to molecular sieve containing materials, such as catalysts, aswell as to sorbents and sorbent containing materials.

BACKGROUND OF THE INVENTION

There exist various industrial processes that utilize substantialquantities of catalysts and/or sorbents in order to manufacturedifferent products. For example, one of the largest consumers ofcatalysts and sorbents is the oil refining industry, which utilizescatalysts/sorbents in different processes, such as the fluid catalyticcracking (FCC) process, the hydrotreating process, the hydrocrackingprocess, and the process of the sorption of sulfur oxides from flue gas,among others. Other industrial processes utilizing catalysts and/orsorbents in other industries include the fertilizer industry, thechemicals sector, and the automotive industry (such as in catalyticconverters).

Within these industrial processes that use catalyst and/or sorbentmaterials, many are based upon utilizing aluminum-containing compoundsas part of the catalyst/sorbent. Additionally, many also containaluminum or non-aluminum containing molecular sieve materials as part ofthe catalyst/sorbent. For example, in the FCC process and in thehydrocracking process, the molecular sieve is a zeolite. Morespecifically, it is a zeolite of the Y-type or the faujasite-type.

Some industrial processes utilize catalyst/sorbents on a periodic basis,meaning that catalyst/sorbent material is loaded into vessels/columnsand is run with little or no change over long periods of time. In otherprocesses, fresh catalyst/sorbent material is periodically orcontinuously added in order to account for reductions in performanceand/or activity due to physical losses, or deactivation due to factorssuch as steam, temperature, time and contaminant metals contained in thefeedstock. One example of such a process requiring replacement orreplenishment of the catalyst/sorbent material is the FCC process.

To the extent additions of fresh catalyst exceed the physical losses ofthe processing unit, there is a need for further withdrawal of spentcatalyst from the unit. Such spent catalyst can no longer functionproperly in the process due to the deposition of sulfur, carbon,vanadium and/or other elements which inhibit or diminish the catalyticactivity. This type of material is often referred to as either spentcatalyst, equilibrium catalyst, or simply as “ECAT.” Typical withdrawalsfrom the FCC process range from a few tons per day, to as much asthirty, or more, tons per day. The methods of disposing of this spentmaterial vary depending on the quality of the material. For instance,material which is low in contaminant metals, and most likely high inremnant activity, is often resold and incorporated in full, or moretypically, as a supplement to the new, or fresh, catalyst being added toanother FCC unit. The spent catalyst may also be used during unit upsetconditions, start-up of the process following a shutdown due to new unitinstallation, maintenance, or other planned or unplanned shutdowns.Spent catalyst that is not capable of suitable performance in anotherrefinery is often disposed of in landfills, or by incorporating it intoother industrial processes/products such as by incorporating it intocement and road pavement. Alternatively, the spent catalyst may haveother catalytic uses in other processes that require a particularproperty of the spent material, such as surface area/sites, or heavymolecule processing capability.

At present, most catalyst is not considered to be hazardous waste, sothe presence of the various metals contained in the catalyst are not ahindrance to normal disposal in landfills. It is possible that in thefuture, government entities in various countries around the world mayimpose regulations that would limit the disposal options, and/or thatwould add a significant economic cost to the disposal operation.

Instead of simple disposal of the entire spent catalyst in landfills,some catalysts that contain expensive or hazardous components can havethose components recovered prior to disposal. Often, the entire catalystis dissolved in order to recover the metals, and then the final solidresidue is made environmentally safe for disposal prior to suchdisposal. One example of this type of material is a hydrotreatingcatalyst, which often contains metals such as Cr and Mo. Other type ofcatalysts subject to recovery may contain large amounts of preciousmetals (i.e., platinum, palladium, etc.), which are valuable.

Improvement of the performance of spent catalyst has also been of greatinterest. The goal is typically to either separate high performingcatalyst from low activity catalyst, or to improve the activity of thebulk catalyst. This has been known to be performed using either magneticseparation or chemical treatment processing of the spent catalyst.However such processes are not routinely utilized upon the bulk of spentcatalyst. The main reason is believed to be that the performanceimprovement per unit cost has not been high enough, when compared tosimply purchasing new catalyst.

There remains a need to find new processes which are capable ofeconomically increasing the performance of spent catalyst, and/or inrecovering metals contained in the catalyst prior to disposal,especially in recovering rare earth materials, which are becomingincreasingly expensive. Some of the objectives of the present inventionare to address these needs, among others, with novel compositions andprocesses, which processes can also be applied to sorbents.

BRIEF SUMMARY OF THE INVENTION

The present inventor has unexpectedly discovered that by reacting afresh or spent catalyst, or sorbent, with a solution containing anextracting agent (such as an acid or a base), where the catalystcontains both alumina and a molecular sieve (and/or a sorbent), andwhere the reaction is performed under mild conditions of treatment suchthat the majority of the base material does not dissolve into thesolution, that the performance of the catalyst improves. Additionally,metals contained in the catalyst, such as Na, Mg, Al, P, S, Cl, K, Ca,V, Fe, Ni, Cu, Zn, Sr, Zn Sb, Ba, La, Ce, Pr, Nd, Pb, their equivalentoxides, or reaction products of elements or their oxides, can be removedfrom the catalyst. Some of the metals that are removed have economicsignificance for re-use (such as the rare earth elements of La, Ce, Prand Nd), while others have negative environmental impact and thus theirremoval for recycling or separate disposal is preferred. Additionally,the present Applicant has discovered that re-incorporating certain ofthe metals back into the improved catalyst also provides improvedperformance benefits.

The performance benefits include, for example, increases in thecrystallinity of the contained molecular sieve and increases in thesurface area of the catalyst. These improvements are almost always foundto occur with some loss in aluminum content of the catalyst. Higheraluminum loss of the catalyst during the processing has been found tolead to some difficulty in separating the solid product from the liquidproduct which contains the dissolved metals. It is therefore one of thefeatures of some embodiments of the present invention that whenutilizing relatively mild conditions (time, temperature, pressure,acid/base concentration, acid/base selection), a relatively large amountof the desired materials (such as rare earth elements and/or theirequivalent oxides) can be removed from the composition, while arelatively small, or even negligible, amount of aluminum is removed fromthe composition. Additionally, it has been found that even in conditionsof moderate severity, an increase in the performance properties results,as indicated by increases in zeolite crystallinity/content and surfacearea. This resulting material can be re-used in various industrialprocesses with improved performance benefits. Alternatively, materialwhich has been reduced in particle size to an extent where it is notconducive to reuse in its current state may be reincorporated into a newphysical shape/form by adding binders/fillers and forming it into ashaped particle, extrudate, or pellet.

More specifically, embodiments of the present invention provide a methodof producing a resulting solution including at least one rare earthelement. The method includes the steps of:

providing a first sample of a rare earth containing material having theat least one rare earth element therein;

reacting the first sample of the rare earth containing material with anextracting agent to extract at least a portion of the at least one rareearth element from the first sample of the rare earth containingmaterial;

separating the reacted first sample, which has lost at least some of theat least one rare earth element previously associated therewith, fromthe extracting agent;

repeating the reacting step for multiple iterations, designated as (n)iterations where (n) is a whole number, with an extracting agent thatalready includes at least some of the rare earth element, but whileusing a sample of a rare earth containing material that differs from thefirst sample of the rare earth containing material, for at least some ofsaid multiple iterations of said reacting step, to further enrich theamount of the at least one rare earth element in the resulting solution;

repeating the separating step for (n) iterations; and

obtaining the resulting solution, which includes the at least one rareearth element extracted from the rare earth containing material duringthe multiple iterations of said reacting step.

In addition, embodiments of the present invention provide a method ofrecovering one or more rare earth elements from a rare earth containingmaterial. The method includes the steps of:

providing the rare earth containing material having aluminum and atleast one rare earth element therein, wherein the weight percentage ofthe aluminum, as its oxide equivalent, is defined as A_(O)% and theweight percentage of the at least one rare earth element, as its oxideequivalent, is defined as R_(O)%; and

reacting the rare earth containing material with a solution to extract arelatively large proportion of at least a portion of the at least onerare earth element from the rare earth containing material, whileextracting only a relatively moderate proportion of the aluminum, suchthat the resulting weight percentage of the at least one rare earthelement, as its oxide equivalent, remaining in the rare earth containingmaterial, defined as R_(F)%, and the resulting weight percentage ofaluminum, as its oxide equivalent, remaining in the rare earthcontaining material, defined as A_(F)%, satisfy the followingrelationships:

R_(F)% is less than or equal to approximately 0.4 R_(O)%; and

A_(F)% is greater than or equal to approximately 0.5 A_(O)%.

Further, embodiments of the present invention provide a method ofrecovering one or more rare earth elements from a rare earth containingmaterial. The method includes the steps of:

providing the rare earth containing material, of a weight W_(RE), havingaluminum and at least one rare earth element therein, wherein the weightpercentage of the aluminum, represented as its weight percent oxideequivalent Al₂O₃, is defined as A_(O)% and the weight percentage of theat least one rare earth element, represented as its weight percent oxideequivalent, is defined as R_(O)%; and

reacting the rare earth containing material with a solution, of a volumeV_(S), to extract a relatively large proportion of at least a portion ofthe at least one rare earth element from the rare earth containingmaterial, while extracting only a relatively moderate proportion of thealuminum, such that the resulting weight percentage of the at least onerare earth element, as its oxide equivalent, remaining in the rare earthcontaining material, defined as R_(F)%, and the resulting weightpercentage of aluminum, as its oxide equivalent, remaining in the rareearth containing material, defined as A_(F)%, satisfy the followingrelationships:

$x = {\frac{R_{o}}{A_{o}} \times \frac{A_{f} - A_{o}}{R_{f} - R_{o}}}$

where x is less than or equal to about 0.8; and

y=W_(RE) (in grams)/V_(S) (in milliliters),

where y is greater than or equal to about 0.025.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Preferred embodiments of the present invention are described herein withreference to the drawings wherein:

FIG. 1 is a flowchart of an example of an embodiment of the presentmethod of recovering rare earth elements from a catalyst; and

FIG. 2 is a flowchart of potential processing steps for the rare earthcontaining solution that results from path 110 of the flowchart of FIG.1

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the present invention relates to methods of recovering oneor more rare earth elements (such as lanthanum (La), cerium (Ce),praseodymium (Pr), neodymium (Nd), etc.) from a rare earth containingmaterial. Turning now to FIGS. 1 and 2, an explanation of the stepsinvolved in examples of some embodiments will be described. Followingthe description of FIGS. 1 and 2, an explanation of some specificexamples will be provided.

Step S1A of FIG. 1 involves providing a sample of the rare earthcontaining material (i.e., a material including at least one rare earthelement therein, such as lanthanum, cerium, praseodymium, neodymium,and/or alloys thereof), which can be in any desired form, wherepreferred forms include powders or extrudates. Further, the rare earthcontaining material (“RE containing material”) provided in Step S1A alsopreferably includes aluminum. For example, in certain embodiments, theRE containing material is a molecular sieve, a material that includes amolecular sieve (both of which will referred to as a “molecular sievecontaining material”), a sorbent, or a sorbent containing material (bothof which will referred to as a “sorbent containing material”) and thatincludes at least one element selected from the following: silicon,phosphorus and aluminum. Preferably, the RE containing material is alsoa zeolite containing material (wherein a zeolite is one particular typeof molecular sieve), one example of such a material is a fluid catalyticcracking (FCC) catalyst. If an FCC catalyst is used, it can be either afresh catalyst (i.e., unused in a FCC process) or a spent catalyst(i.e., previously used in a FCC process). Similarly, if another type ofcatalyst is used, it could also be fresh or spent. Prior to Step S1A,the spent catalyst, if being used, may be washed, de-oiled, orcalcined/roasted if necessary, by any methods known to those of ordinaryskill in the art.

Step S1B involves providing an extracting agent, which is a materialthat can extract at least some of the rare earth element from the REcontaining material. It is contemplated that the extracting agent can bein any form (liquid solid, gas). In certain embodiments, the extractingagent is an acidic or basic solution. Preferably, when using such anacidic or basic solution, the extracting agent is a liquid solutionhaving a pH of either less than approximately 6 or greater thanapproximately 8. More preferably, such a liquid solution will have a pHof either less than approximately 3 or greater than approximately 10.

For example, the extracting agent could be a solution of water and oneor more of the following: (a) nitric acid; (b) hydrochloric acid; (c)maleic acid; (d) formic acid; (e) sulfuric acid; (f) acetic acid; (g)ammonium citrate; (h) ammonium hydroxide; (i) ammonium chloride; (j)ammonium sulfate, (k) ethylenediamine, etc. Of course, the acids andbases listed herein are examples only, and other acids or bases are alsocontemplated as being within the scope of the invention.

Steps S1A* and S1B* of FIG. 1 are optional steps showing that the REcontaining material and/or the extracting agent can be heated beforeproceeding to Step S2, which is a step of reacting the RE containingmaterial with the extracting agent. Such heat of Steps S1A* and S1B* canbe applied in any desired manner, such as by placing the materialintended to be heated into an oven, or other heat producing device, orby directly heating the vessel within which the material is contained,such as by applying a flame to the exterior of the vessel. The choice ofwhether to apply heat to the RE containing material, the extractingagent, to neither, or to both depends on a variety of circumstances. Forexample, applying heat to either the RE containing material or theextracting agent, or both, can, with certain combinations of REcontaining materials and extracting agents, reduce the required reactingtime of Step S2. On the other hand, with certain extracting agents, suchas sulfuric acid or hydrochloric acid, heat is not necessary and thereaction proceeds relatively quickly even in the absence of theapplication of heat.

Turning now to Step S2, this step is the step of reacting the REcontaining material with the extracting agent. During this step, thefirst sample of the RE containing material (of Step S1A) is reacted withthe extracting agent (of Step S1B) to extract at least a portion of theat least one rare earth element from the first sample of the REcontaining material.

The reacting step (Step S2) may be accomplished in any of a variety ofdifferent ways, depending upon a number of different factors, such asthe specific material and the specific agent being reacted, the desiredmaterial being extracted, the desired time available for the process,the scale of the process (i.e., the weights/volumes of the materialbeing reacted), the particular conditions or states of the materials,etc. Examples of the types of equipment that can be utilized in thereacting step include mix tanks and in-line mixers. Thus, such reactingstep can be performed using either a batch process or in a continuousmode.

In certain embodiments, the extracting agent is a liquid solution (suchas an acidic or basic solution) and the RE containing material is asolid in the form of a power, an extrudate, pellets, or microspheres. Insuch situations, the extracting agent and the RE containing material canbe mixed together in any appropriate vessel (with agitation, such asstirring, if desired). Alternately, in such embodiments, the REcontaining material can be placed within an appropriate vessel, and theextracting agent can merely be passed over the RE containing material.Such a process may be accomplished, for example, by using a vessel thathas a screen, or similar filter, as its bottom interior surface, and bysimply pouring the liquid solution over the RE containing material,whereby after the solution contacts the RE containing material, theliquid solution (including the extracted RE material) passes through thescreen, while the RE containing material (which now includes less rareearth (RE) material than before such contact due to the extraction)remains on the screen within the vessel.

In other embodiments, it is contemplated that the extracting agent couldbe a solid or a gas. In either case (as well as with a liquid extractingagent), contact with the extracting agent must be of the type andsufficiency such that at least a portion of the RE is extracted from theRE containing material.

As represented by Step S2*, which is another optional step, heat may beoptionally applied to the combination of the RE containing material andthe extracting agent, which may be in the form of a slurry, during thereacting step, for the same purposes and by the same methods describedabove. For example, heat can be applied such that the liquid solutionreaches a maximum temperature between the range of at leastapproximately 45° C. and approximately 130° C. Thus, heat can be appliedduring any one, or more, of the following steps, Step S1A*, Step S1B*and/or Step S2* (where the * represents that the step is optional).

Next, the process continues to Step S3, which is a step of separatingthe reacted first sample (which has lost at least some of the at leastone rare earth element previously associated therewith) from theextracting agent. For this step, any known separation method may beused. In certain embodiments, during this step, the remains of the firstsample of the RE containing material after the reacting step (Step S2)will be in the form of a solid, and the extracting agent (which willinclude the extracted rare earth element(s) in solution) will be in theform of a liquid. Thus, for such embodiments, the materials aretransferred to a liquid-solid separator within which any knownsolid/liquid separation technique may be used.

For example, the solids may be separated from the liquid by filtration(such as with a vertical type centrifugal filter, a vacuum filter, aplate and frame filter, etc.), using decantation, centrifugation,settling, etc., or any other methods, or combinations of methods, knownto those of ordinary skill in the art. Optionally, a rinsing liquid,such as water, a liquid containing an acid or base, or combinationsthereof may be applied to the solids after separation, as represented bypath 30. Such rinsing liquid can be used to remove the extracting agentthat has adhered, or otherwise remains, on the separated solids and/orto neutralize the separated solids prior to disposal or use in furtherprocess steps. After the rinsing liquid passes through the liquid-solidseparator (path 40), the rinse liquor may be re-cycled back into theliquid solid separator along path 50 to rinse the next batch ofseparated solids (or to further rinse the present batch), either with orwithout the addition of fresh rinse liquid (path 30). As a secondalternative, the rinse liquor may be directed to enter the liquid sideof the process along path 60, in which case the rinse liquor is combinedwith the liquid solution that was separated during Step S3. Or, as athird alternative, the rinse liquor may be directed along path 70 fordisposal (Step S5) in any known manner

In embodiments in which the rare earth element was located upon amolecular sieve containing material, such as a catalyst, the solids willconsist of the molecular sieve containing material and any other solidmaterials that have been extracted, but that are not in solution withthe liquid solution; and the liquid will consist of the liquid acidic orthe liquid basic solution with the rare earth material as part of thesolution, if such liquid solution was used as the extracting agent. Forexample, in an embodiment in which the RE containing material is anECAT, the solids will consist of the molecular sieve catalyst, whichwill still include the bulk of the primary materials attached to themolecular sieve (such as the aluminum and the silicon) and the liquidwill consist of the acidic or basic solution (depending on the type ofextracting agent used) with the rare earth materials (such as lanthanum(La), cerium (Ce), praseodymium (Pr) and neodymium (Nd)) extractedduring the reacting step (Step S3) in solution with the liquid (such asa solution that includes La (NO₃)₃ and (H₂O)).

In embodiments in which Step S3 is a solid/liquid separating step, thesolids that have been separated from the liquid (by any one or more ofthe methods mentioned above, such as filtration, decanting, through theuse of a centrifuge, etc.) may take either of two paths, designated aspaths 10 and 20. As explained more fully below, path 10 is a path inwhich the solids are run through the procedure again, starting prior tothe optional heating step (Step S1A*), either with or without theoptional heating step (Step S1A*), and path 20 is a path in which thesolids are removed from the system for either disposal or for re-use(with any optional further treatments required for such re-use, asnecessary). It is also contemplated that part of the solids could goalong path 10 and that part could go along path 20. Further, it shouldbe noted that paths 10 and 20 may not contain all of the solids, becausethe liquid of paths 40 and 75 may also include some solids that can beseparated out by further processes.

More specifically, starting with the path 10, the solids, which, forexample, may be an FCC catalyst that has had at least some of the rareearth elements removed therefrom by the Step S2, may be run through theprocess again, starting at either the optional heating step (Step S1A*)or at the reacting step (Step S2), if one desires to attempt to extractadditional material, such as one or more additional rare earth elements,from the catalyst. If desired, the solids may be run through the process(i.e., the procedure may include path 10) for any number of iterations.Further, it is also contemplated that the solids of path 10 could bestored for use in future processes of the type demonstrated by FIG. 1,or that they could be used in a separate process of the typedemonstrated by FIG. 1 that is being run in parallel with the presentprocess.

In certain embodiments, at least some of the samples of the REcontaining material used during the multiple iterations of the reactingstep (Step S2) include the same rare earth element as the first sampleof the RE containing material. For example, if two or more rare earthmaterials are being focused on, such as lanthanum and cerium, at leastsome of the sample of the RE containing material should includelanthanum and at least some should contain cerium, but all samples neednot contain both lanthanum and cerium. However, it is preferably if allof the samples of the RE containing material used during the multipleiterations of the reacting step include the same rare earth element asthe first sample of the RE containing material in order to increase theyield of that rare earth material. Further, it is also preferably thatat least some, and more preferable that most or all, of the samples ofRE containing material used during the multiple iterations of thereacting step have essentially the same chemical composition as thechemical composition of the first sample of the RE containing material,which improves the efficiency of the process.

Turning back to FIG. 1, if path 20 is followed instead of path 10, thesolids may optionally be washed in optional Step S4A*, prior to movingto Step S4A, where the solids are disposed of in any desired mannerknown to those of ordinary skill in the art (such as in a landfill or asan added component to roadway material) or re-used (in a processrequiring a catalyst, such as in an FCC process). If the optionalwashing step (Step S4A*) is selected, the solids may be washed with anyappropriate liquid, such as water, an acidic solution or a basicsolution.

If necessary and desired, the solids of Step S4A may be the subject offurther treatment to reactivate them, such as, for example, byundergoing a process in which materials are added back into the solidsso that they can be re-used for their originally intended purpose, suchas an FCC catalyst. Alternately, it is also contemplated that the solidsof Step S4A could be used for a purpose different from the one that theywere originally designed for.

In certain embodiments, the resulting solids that have undergone theprocess of FIG. 1 could actually perform their designated catalyticfunctions better than even the original, un-treated catalyst, eitherwith or without adding the rare earth materials to the molecular sieve.Example of such situations will be explained in more detail below whendiscussing Table 2, after discussing some specific examples ofembodiments of the process in Tables 1A-1C.

Turning again to FIG. 1, although both paths 10 and 20 have been shownin the flowchart of this figure, Applicant believes that in mostsituations, path 10 will not be taken very frequently due to therelatively high efficiency of the step in which the rare earth compoundsare removed from the solids, and thus the solids will not normally bere-introduced into the system. Instead, path 20, in which the solids areremoved for re-use or disposal, will be the more frequently chosenoption.

Returning to Step S3 of FIG. 1, as the path of the solids has alreadybeen described (along one of path 10 or path 20), the path of the liquidseparated by the liquid-solid separator, if such a device is used, willbe described next. The liquid separated by the liquid-solid separator inStep S3 travels along path 75, where it is further directed along eitherpath 80 or along path 90 (or with some liquid directed along each path).If it is directed along path 80, the liquid is run through the procedureagain, starting with the heating step (Step S1B*), which is optional,and continuing with the reacting step (Step S2), etc. The liquidtravelling along path 80, which will include the rare earth elementextracted from the RE-containing material during the reacting step (StepS2), can thus be further enriched with an additional amount of the rareearth element by being run through the process again, especially if thereacting step is performed with a new sample of the RE containingmaterial (such as with a new sample of ECAT) in Step S1A.

In other words, the reacting step (Step S2) may be repeated for multipleiterations, which can be designated as (n) iterations (where (n) is awhole number) with an extracting agent that already includes at leastsome of the rare earth element, but while using a sample of a rare earthcontaining material that differs from the first sample of the rare earthcontaining material, for at least some of the multiple iterations of thereacting step (Step S2). Such repeated iterations further enrich theamount of the at least one rare earth element in the resulting solution.It is contemplated that the multiple iterations could include iterationsin which fresh extracting agent are combined with iterations in whichextracting agent from the process of FIG. 1 (i.e., the path 80 solution)in any desired manner (such as a simple alternating pattern, a patternin which multiple iterations of path 80 solution are run for every oneiteration of fresh extracting agent, a pattern in which multipleiterations of fresh extracting agent are run for every one iteration ofthe path 80 solution, an irregular sequence, etc.).

Preferably, during each successive iteration of the reacting step (stepS2), the amount of the rare earth element in the extracting agent usedduring a particular iteration of the reacting step is greater than orapproximately equal to the amount of rare earth element in theextracting agent of the immediately preceding iteration of the reactingstep. Thus, the extracting agent is preferably further enriched withmore and more rare earth material in each iteration of the process.

Another preference is that that during each successive iteration of thereacting step, the amount of the rare earth element in the RE containingmaterial (such as a molecular sieve containing material) used during aparticular iteration of the reacting step is greater than orapproximately equal to the amount of rare earth element in the molecularsieve containing material of the immediately preceding iteration of thereacting step. In other words, it is preferred that different samples ofRE containing material are introduced in Step S1A for each iteration(regardless of whether materials such as spent catalyst or freshcatalyst are used), instead of using the process along path 10 of FIG.1, which re-uses the same RE containing material in further iterations.This is the case because the re-used RE material is has already had someof rare earth materials extracted, and thus further extraction is moredifficult.

In some embodiments, the process may be repeated for only a fewiterations (where n equals between 2 and 10 iterations), or it may berepeated for a large amount of iterations (in the hundreds range, suchas n equals at least 200 or at least 300, or more), or it may berepeated for a moderate number of iterations, which would be a rangebetween the few iterations and the large amount of iterations mentionedpreviously.

As with the solids of path 10, it is also contemplated that the liquidof path 80 could be stored for use in future processes of the typedemonstrated by FIG. 1, or that it could be used in a separate processof the type demonstrated by FIG. 1 that is being run in parallel withthe present process.

As an alternative to having the liquid that was separated by theliquid-solid separator in Step S3 travel along path 80 (for anotheriteration in the process), it could instead travel along path 90 to Step54B*, which is an optional step (like all steps marked with the symbol*) in which the liquid solution is purified for reuse in anotheriteration of the process (path 100) and the reject and rare earthmaterials are separated from the solution, and which reject and rareearth materials can be sold, used in a different process, or disposed ofif they are of little value. Thus, the solution of path 100 differs fromthe solution of path 80 because the solution of path 100 has beenpurified, and the metals, such as lead, nickel, iron and the rare earthmaterials have been at least partially removed from the solution, whilethe solution of path 80 has not been purified, and thus includes thereject materials, as well as the rare earth materials.

The optional purification/separation step (Step S4B*) may be performedby any known process. For example, the optional purification/separationstep my be performed by any known acid recovery process, such as aprocess known as diffusion dialysis, which works by transferring theused acid through an anion exchange membrane against a counter-flowingwater stream. Briefly, in this process, as known in the art, the acidsolution (solute) is on one side of the membrane, and the de-ionizedwater (solvent) is on the other side, moving in the opposite directionwithin a single container. The acid passes, or diffuses, through themembrane and into the water, resulting in the reclaimed acid exiting thecontainer from the water side. However, the reject metals and rare earthmaterials, along with a low percentage (normally approximately 15%) ofacid that is associated with the metals, cannot pass through themembrane, and therefore exit the container from the acid side. Devicesfor accomplishing such processes are available from a variety ofsources, such as from: Pure Cycle Environmental LLC. Of North havenConn. (www.purecycle.com). Presumably, the optionalpurification/separation step (Step S4B*) could be performed withmaterials other than acids, such as with a base.

If the optional purification/step (Step S4B*) is not performed, theprocess can run along path 110 and be terminated (after the desirednumber of iterations along path 80), and the resulting solution (whichincludes the RE materials that have been extracted) can be used for anydesired purpose. For example, it can be sold as is, or it can be furtherprocessed to remove the valuable RE materials from the solution by anyknown method, such as with selective precipitation, which is a processknown to those of ordinary skill in the art.

Briefly, with such a process of selective precipitation, a base isslowly added to the resulting solution to increase the pH of thesolution to a desired narrow range, at which point certain materialsbegin to precipitate out of the solution, and can thus be removed byfiltration or other solid/liquid separation techniques. Then, the baseis again slowly added to increase the pH of the solution to anotherdesired narrow range (higher than the first range), at which pointcertain other materials begin to precipitate out of the solution, andcan thus be removed by filtration or other solid/liquid separationtechniques. The process is continued until all of the desired rare earthmaterials have been removed from the solution. In the alternative, otherknown methods, such as solvent extraction, could also be used to removethe valuable rare earth materials from the resulting solution, ifdesired.

In order to help visualize some of the previously-discussed optionsavailable for the resulting rare earth containing solution oftermination path 110 of FIG. 1, the chart of FIG. 2 has been provided.Starting with Step S10, which is initial step (i.e., where the rareearth (RE) containing solution from path 110 of FIG. 1 is provided), theprocess can continue along any of the following paths:

(i) along path 120 to Step S12, in which no further processing takesplace and the RE containing solution is used for a different process,sold to a third party, etc;

(ii) along path 130 to Step S14, which is a step of separating theoriginal extractant (extracting agent) from the extracted metals, asdescribed below;

(iii) along path 135 to Step S18, which is which is a step ofevaporating, or partially evaporating, the solution, as described below;or

(iv) along path 145 to Step S30, which is a purification step, asdescribed below.

Details of example processes for Steps S14, S18, and S30, and otherrelated steps, will be described next.

Step S14 could be any desired acid (or base) recovery process, such asthe diffusion dialysis process discussed above, that could be used forseparating the original extractant (extracting agent) from the extractedmetals. After completing Step S14, the recovered extractant (extractingagent) from which all, or at least most, of the reject metals (such aslead nickel, and iron) and the RE material have been removed, movesalong path 140 to Step S16, which returns the extractant (extractingagent) to the process of FIG. 1 (along path 100 of FIG. 1).

The extracted metals (such as lead, nickel, and iron and the REmaterials) from Step S14, which are found in a solution that isrelatively extractant free, can be recovered by any known method fromthe remaining solution by proceeding to Step S18, which is a step ofevaporating, or partially evaporating, the solution. The result of StepS18 can proceed along one of the following three paths: path 150, path160 or path 170, as described below.

If path 150 is selected, there is no further processing (see terminalStep S20), and the result is, for example, a powder that is rich in rareearth hydroxides. Since the rare earth materials are valuable, suchpowder could be sold, and the rare earth materials could be recycledinto new catalysts, or into any other type of product that utilizes suchmaterials.

If path 160 is selected, the resulting solids after evaporation could bedissolved in a reagent (which, in preferred embodiments, could be acidicor basic) in Step S22, which results in a rare earth rich solution (seeterminal Step S24), which can be sold to any third party user of such asolution, or used for any desired purposes. In certain embodiments, thesolution of terminal Step S24 will have an acidic or basic concentrationof between approximately 0.1 molar and approximately 25 molar.

Preferably, the resulting solution of Step S24, will include at least20%, on an oxide basis, of the at least one rare earth element that wasextracted from the rare earth containing material, after performing thereacting step (Step S2 of FIG. 1) multiple times. And even morepreferably, the resulting solution, after performing the reacting stepmultiple times, will includes at least 30% on an oxide basis, of the atleast one rare earth element that was extracted from the rare earthcontaining material.

If path 170 is selected, the calcine/roast process of Step S26 can beperformed by heating the solution or residue to elevated temperatures,and the resulting product can either be passed along path 180 toterminal Step S28, which involves no further processing and results in apowder that is rich in rare earth oxides, or the resulting product cango along path 190 to Steps S22 and Step S24, as described above. Thecombination of process Step S18, path 170, process Step S26, path 190and process Step S22 can be used (instead of merely going from processStep S18, path 160 to process Step S22 (i.e. omitting Step S26)) tofacilitate the dissolving process of Step S22.

As an alternative to proceeding from Step S22 (the dissolving in reagentstep) to terminal Step S24, the process may instead pass from Step S22to Step S30 for further purification, such as by using the selectiveprecipitation process described above. The resulting solids from StepS30 will, in preferred embodiments, require no further processing, asindicated by Step S20, which shows that in certain embodiments, thesesolids will be in the form of a powder that is rich in rare earthhydroxides. The resulting liquid from Step S30 can be either disposed ofor reclaimed, if desired, as indicated by Step S32.

Next, various specific examples of the embodiments of the process willbe described in detail, while referring to Tables 1A-1C. Of course,these examples are for the purpose of explanation only, and should notbe considered as limiting the scope of the invention.

TABLE 1A Example Reagent Catalyst Reagent gr Cat/ml Time No Acid/BaseReagent/Conditions Concentration Catalyst Qty, gr Qty, ml Reagent Tmax(C) (hrs) 1, RE-A — — — ECAT A — — — 2 Acid Nitric Acid 16M ECAT A 14200 0.07 80 3.5 3 Base Ammonium Citrate  1M ECAT A 25 100 0.25 78 1.75 4Acid Nitric Acid 16M ECAT A 25 100 0.25 46 2.25 5 Acid Nitric Acid 16MECAT A 100 100 1.00 76 1.5 6 Acid Sulfuric Acid 96% ECAT A 25 100 0.2590 2 7 Acid Hydrochloric Acid 12M ECAT A 25 100 0.25 90 2 8 Acid AceticAcid 84% ECAT A 25 100 0.25 80 2 9 Acid Nitric Acid 16M ECAT A 20 2000.10 60 1.5 10, RE-B — — — ECAT B — — — 11 Acid Nitric Acid 16M ECAT B25 100 0.25 82 3.25 12, RE-C — — — ECAT C — — — 13 Acid Nitric Acid 16MECAT C 2 200 0.01 117 (reflux) 16 14 Acid Nitric Acid 16M ECAT C 75 3000.25 114 (reflux) 16 15 Acid Nitric Acid  2M ECAT C 25 75 0.33 100(reflux) <0.25 16 Acid Hydrochloric Acid 10M ECAT C 75 300 0.25 29 1 17Acid Nitric Acid 16M ECAT C 75 300 0.25 120 (reflux) 0.6 18 AcidHydrochloric Acid 10M ECAT C 75 300 0.25 115 (reflux) 14 19 Acid NitricAcid, Recycled ECAT C 30 122 0.25 75 (reflux) 0.2 20 Acid HydrochloricAcid 10M ECAT C 75 300 0.25 70 (reflux) 0.1 21 Acid Example 20 FiltrateRecycled ECAT C 50 200 0.25 76 (reflux) 0.1 22 Acid Hydrochloric Acid10M ECAT C 75 300 0.25 29 1 23 Acid Hydrochloric Acid 10M ECAT C + La 24Acid Heat Acid, Batch 3 16M ECAT C 25 75 0.33 100 <0.25 25 Acid HeatAcid, 5 um filter, Batch 3 16M ECAT C 25 75 0.33 100 <0.25 26 Acid HeatPowder, Batch 3 16M ECAT C 25 75 0.33 100 <0.25 27 Acid Heat Acid + HeatPowder, Batch 1 16M ECAT C 25 75 0.33 100 <0.25 28 Acid Heat Acid + HeatPowder, Batch 3 16M ECAT C 25 75 0.33 100 <0.25 29, RE-D — — — FreshCatalyst A — — 30 Acid Nitric Acid 16M Fresh Catalyst A 25 100 0.25 780.6 31 Acid Nitric Acid 16M Fresh Catalyst A 75 300 0.25 120 (reflux)0.6

TABLE 1B Example Acid/ Reagent No Base Reagent/Conditions ConcentrationAl₂O₃ SiO₂ La₂O₃ CeO₂ Pr₆O₁₁ 1, RE-A — — — 54.3% 40.4% 1.1% 0.22% 0.09%2 Acid Nitric Acid 16M 50.4% 46.1% 0.1% 0.04% 0.05% 3 Base AmmoniumCitrate  1M 52.7% 42.7% 0.7% 0.15% 0.05% 4 Acid Nitric Acid 16M 52.8%43.0% 0.3% 0.10% 0.00% 5 Acid Nitric Acid 16M 51.7% 44.5% 0.3% 0.06%0.04% 6 Acid Sulfuric Acid 96% 53.2% 42.5% 0.6% 0.10% 0.06% 7 AcidHydrochloric Acid 12M 52.6% 43.9% 0.2% 0.04% 0.00% 8 Acid Acetic Acid84% 53.0% 41.8% 0.9% 0.19% 0.08% 9 Acid Nitric Acid 16M 51.5% 44.4% 0.3%0.09% 0.03% 10, RE-B — — — 48.5% 44.9% 2.4% 0.11% 0.02% 11 Acid NitricAcid 16M 47.1% 48.5% 0.7% 0.07% 0.00% 12, RE-C — — — 59.4% 34.1% 2.4%0.03% 0.00% 13 Acid Nitric Acid 16M 22.4% 73.3% 0.6% 0.02% 0.00% 14 AcidNitric Acid 16M 54.3% 41.0% 1.2% 0.02% 0.00% 15 Acid Nitric Acid  2M60.0% 35.8% 0.6% 0.02% 0.00% 16 Acid Hydrochloric Acid 10M 59.8% 35.1%1.2% 0.02% 0.00% 17 Acid Nitric Acid 16M 57.1% 38.4% 0.8% 0.02% 0.00% 18Acid Hydrochloric Acid 10M 36.7% 58.5% 0.9% 0.01% 0.00% 19 Acid NitricAcid, Recycled 59.8% 35.4% 0.9% 0.02% 0.04% 20 Acid Hydrochloric Acid10M 59.5% 36.3% 0.6% 0.02% 0.00% 21 Acid Example 20 60.0% 35.1% 1.0%0.02% 0.00% Filtrate Recycled 22 Acid Hydrochloric Acid 10M 59.8% 35.1%1.2% 0.02% 0.00% 23 Acid Hydrochloric Acid 10M 55.3% 38.7% 2.4% 0.00%0.00% 24 Acid Heat Acid, Batch 3 16M 59.9% 34.7% 1.5% 0.03% 0.00% 25Acid Heat Acid, 5 um 16M 60.1% 35.2% 0.9% 0.02% 0.00% filter, Batch 3 26Acid Heat Powder, Batch 3 16M 59.5% 34.8% 1.7% 0.03% 0.03% 27 Acid HeatAcid + Heat 16M 60.0% 35.0% 1.2% 0.02% 0.00% Powder, Batch 1 28 AcidHeat Acid + Heat 16M 60.0% 34.1% 1.9% 0.04% 0.00% Powder, Batch 3 29,RE-D — — — 36.5% 57.4% 3.2% 0.02% 0.00% 30 Acid Nitric Acid 16M 26.9%70.1% 0.1% 0.00% 0.00% 31 Acid Nitric Acid 16M 25.2% 71.6% 0.4% 0.00%0.00% Example No Nd₂O₃ Na₂O MgO Fe₂O₃ V₂O₅ NiO PbO 1, RE-A 0.12% 0.56%0.00% 0.77% 0.18% 0.27% 0.01% 2 0.01% 0.31% 0.00% 0.78% 0.14% 0.32%0.00% 3 0.07% 0.42% 0.00% 0.83% 0.12% 0.31% 0.00% 4 0.02% 0.43% 0.00%0.86% 0.14% 0.33% 0.01% 5 0.02% 0.42% 0.00% 0.88% 0.14% 0.33% 0.01% 60.06% 0.40% 0.00% 0.85% 0.13% 0.32% 0.01% 7 0.02% 0.39% 0.00% 0.80%0.13% 0.31% 0.00% 8 0.11% 0.49% 0.00% 0.88% 0.19% 0.33% 0.01% 9 0.03%0.45% 0.00% 0.89% 0.14% 0.33% 0.01% 10, RE-B 0.01% 0.40% 0.14% 0.92%0.39% 0.23% 0.05% 11 0.00% 0.21% 0.05% 0.87% 0.30% 0.24% 0.03% 12, RE-C0.05% 0.49% 0.00% 0.86% 0.79% 0.40% 0.02% 13 0.00% 0.12% 0.00% 0.58%0.30% 0.34% 0.00% 14 0.00% 0.22% 0.00% 0.69% 0.60% 0.35% 0.01% 15 0.00%0.31% 0.00% 0.82% 0.63% 0.42% 0.02% 16 0.03% 0.40% 0.00% 0.90% 0.67%0.41% 0.02% 17 0.00% 0.19% 0.00% 0.80% 0.73% 0.44% 0.02% 18 0.00% 0.18%0.00% 0.79% 0.46% 0.40% 0.01% 19 0.00% 0.39% 0.00% 0.88% 0.68% 0.42%0.02% 20 0.00% 0.34% 0.00% 0.79% 0.63% 0.42% 0.02% 21 0.02% 0.39% 0.00%0.85% 0.65% 0.42% 0.02% 22 0.03% 0.40% 0.00% 0.90% 0.67% 0.41% 0.02% 230.02% 0.18% 0.00% 0.74% 0.70% 0.39% 0.01% 24 0.00% 0.40% 0.00% 0.86%0.71% 0.42% 0.02% 25 0.00% 0.39% 0.00% 0.85% 0.69% 0.41% 0.01% 26 0.03%0.41% 0.00% 0.86% 0.69% 0.40% 0.02% 27 0.02% 0.32% 0.00% 0.83% 0.69%0.40% 0.02% 28 0.03% 0.45% 0.00% 0.84% 0.72% 0.40% 0.02% 29, RE-D 0.00%0.21% 0.00% 0.63% 0.01% 0.01% 0.01% 30 0.00% 0.00% 0.00% 0.52% 0.02%0.03% 0.00% 31 0.00% 0.00% 0.00% 0.46% 0.00% 0.02% 0.00%

TABLE 1C % Al₂O₃ Removed/ % Al₂O₃ % RE₂O₃ Example Acid/ Reagent/ Reagent% RE₂O₃ % RE₂O₃ Removal Removed No Base Conditions ConcentrationCatalyst (R) Removal (A) (x) 1, RE-A — — — ECAT A 1.48%  0%    0% 2 AcidNitric Acid 16M ECAT A 0.25% 83%    7% 0.1 3 Base Ammonium Citrate  1MECAT A 0.91% 38%    3% 0.1 4 Acid Nitric Acid 16M ECAT A 0.45% 70%    3%0.0 5 Acid Nitric Acid 16M ECAT A 0.37% 75%    5% 0.1 6 Acid SulfuricAcid 96% ECAT A 0.80% 46%    2% 0.0 7 Acid Hydrochloric Acid 12M ECAT A0.30% 80%    3% 0.0 8 Acid Acetic Acid 84% ECAT A 1.32% 11%    2% 0.2 9Acid Nitric Acid 16M ECAT A 0.41% 73%    5% 0.1 10, RE-B — — — ECAT B2.58%  0%    0% 11 Acid Nitric Acid 16M ECAT B 0.78% 70%    3% 0.0 12,RE-C — — — ECAT C 2.53%  0%    0% 13 Acid Nitric Acid 16M ECAT C 0.59%77%   62% 0.8 14 Acid Nitric Acid 16M ECAT C 1.27% 50%    9% 0.2 15 AcidNitric Acid  2M ECAT C 0.58% 77%  −1% 0.0 16 Acid Hydrochloric Acid 10MECAT C 1.23% 51%  −1% 0.0 17 Acid Nitric Acid 16M ECAT C 0.84% 67%    4%0.1 18 Acid Hydrochloric Acid 10M ECAT C 0.94% 63%   38% 0.6 19 AcidNitric Acid, Recycled ECAT C 0.92% 64%  −1% 0.0 20 Acid HydrochloricAcid 10M ECAT C 0.65% 74%    0% 0.0 21 Acid Example 20 Filtrate RecycledECAT C 1.04% 59%  −1% 0.0 22 Acid Hydrochloric Acid 10M ECAT C 1.23% 51% −1% 0.0 23 Acid Hydrochloric Acid 10M ECAT C + La 2.41%  5%    7% 1.524 Acid Heat Acid, Batch 3 16M ECAT C 1.52% 40%  −1% 0.0 25 Acid HeatAcid, Sum filter, Batch 3 16M ECAT C 0.88% 65%  −1% 0.0 26 Acid HeatPowder, Batch 3 16M ECAT C 1.76% 30%    0% 0.0 27 Acid Heat Acid + HeatPowder, Batch 1 16M ECAT C 1.27% 50%  −1% 0.0 28 Acid Heat Acid + HeatPowder, Batch 3 16M ECAT C 1.98% 22%  −1% 0.0 29, RE-D — — — FreshCatalyst A 3.26%  0%    0% 30 Acid Nitric Acid 16M Fresh Catalyst A0.11% 97%   26% 0.3 31 Acid Nitric Acid 16M Fresh Catalyst A 0.40% 88%  31% 0.4

Tables 1A-1C, above, show the results of a number of differentexperiments using various embodiments of the process outlined above.Tables 1A-1C show the results of performing the process upon fourdifferent RE-containing materials, designated as RE-A; RE-B; RE-C andRE-D. In three of the four cases provided for in Tables 1A-1C, theRE-containing material was a spent FCC catalyst (an ECAT, designated asECAT A, ECAT B, and ECAT C) and in the fourth case, it was a fresh FCCcatalyst (designated as “Fresh Catalyst A”). Tables 1A-1C all relate tothe same experiments (thus, Example Nos. 1-31 of Table 1A reference thesame experiments as Example Nos. 1-31 of Tables 1B and 1C), but witheach table focusing on different types of data.

Briefly, the first few columns of each of Tables 1A-1C are the same tofacilitate understanding of the data of each of the tables. Morespecifically, the first column of each table shows the Example Number(from 1-31), where Example Nos. 1-9 utilized RE-A (which is ECAT-A, asseen from the fifth column), Examples 10 and 11 utilized RE-B (which isECAT-B, as seen from the fifth column), Example Nos. 12-28 utilized RE-C(which is ECAT-C, as seen from the fifth column), and Example Nos. 29-31utilized RE-D (which is Fresh Catalyst A, as seen from the fifthcolumn). The second column of Tables 1A-1C shows whether the extractingagent (reagent) is an acid or a base, and the third column shows thespecific acid or base, along with any special conditions, such asExample No. 19 using recycled nitric acid, Example No. 21 using thefiltrate recycled from Example No. 19, etc., as additionally describedbelow. The fourth column of each of Tables 1A-1C shows the molarconcentration of the reagent (extracting agent) used.

Example Nos. 1, 10, 12 and 29 merely show the original conditions ofeach of the four catalyst samples, and thus some of the columns ofTables 1A-1C (such as the Acid/Base designation, the Reagent/Conditionsdescription, the Reagent Concentration, etc.) are not applicable becausethe catalyst has not been acted upon, and thus these columns are leftblank (or designated by a dash “-”).

Columns 6-10 of Table 1A show various details each experiment, such asthe quantity of catalyst utilized, in grams (“Catalyst Qty, gr”); thequantity of reagent (extracting agent) utilized, in milliliters(“Reagent Qty, ml”); the result of the ratio of the quantity of catalystutilized, in grams to the quantity of reagent (extracting agent)utilized, in milliliters (“gr Cat/ml Reagent”), i.e., the ratio ofcolumn 6 over column 7; the maximum temperature that the combination ofthe catalyst and the reagent (extracting agent) was heated to, indegrees Celsius (“Tmax (C)”); and the amount of time that the catalystwas in contact with the reagent (extracting agent), in hours (“Time(hrs)”).

Preferably, at least at least 10 grams of the rare earth containingmaterial (column 6 of Table 1A) are provided for each 100 milliliters ofthe extracting agent (column 7 of Table 1A). Even more preferably, atleast 20 grams of the rare earth containing material are provided foreach 100 milliliters of the extracting agent.

Chemical analysis was performed on samples using wavelength dispersivex-ray fluorescence (Bruker SRS3000) using samples prepared by firstheating the sample to 732-1000 C, followed by preparing glass beads byfusion. The results of such chemical analysis are shown in Table 1B, foreach of the following materials: Al₂O₃, SiO₂, La₂O₃, CeO₂, Pr₂O₃, Nd₂O₃,Na₂O, Fe₂O₃, V₂O₅, NiO and PbO.

A representative example of the conditions utilized in the currentprocess is as follows, with details from Table 1A: The amount (in grams)of the catalyst listed in the “Catalyst Qty” column of the catalystspecified in the “Catalyst” column was added to the amount (in ml) ofreagent specified under the “Reagent Qty” column of the particularreagent listed in the “Reagent/Conditions” column, where the reagent hadthe concentration listed in the “Reagent Concentration.” The mixture washeated to approximately to the temperature (C) listed in the “Tmax”column, for approximately the time (in hours) listed in the “Time”column. Afterwards, the solid and liquid were separated using a porousceramic filter (such as a filter with a pore size of between 160-250micron) under either vacuum filtration conditions or settling. Theresulting filtrate was then further separated by settling or finer poresize ceramic filter (such as 5-6 micron pore size). Select samples offiltrate were analyzed by x-ray fluorescence and found to typicallycontain the following elements Al, P, K, Ca, Ti, V, Fe, Ni, Cu, Sr, Ba,La, Ce, Pr, Nd. Quantitative analysis on the solid was analyzed by x-rayfluorescence, and the results are reported in Table 1B forrepresentative samples prepared in Table 1A. Table 1C shows ratios ofrare earth (RE) oxides, RE₂O₃ (which is the sum of the rare earth oxidesbased on adding La, Ce, Pr, and Nd from Table 1B), and the improvementscompared with the base case of each example set the Lanthanum oxide,La₂O₃, Aluminum oxide, Al₂O₃. Table 1C also shows the percent Al₂O₃removed divided by the percent RE₂O₃ removed. Additionally, the percentAl₂O₃ removed divided by the percent La₂O₃ removed is also shown inTable 1C.

Additional details regarding the examples of Tables 1A-1C follow:

Examples 2-9 show the effect of varying the reagent, reagent amount,reagent concentration, mixture temperature, time, and rare earthcontaining material quantity using a refinery FCC equilibrium catalyst(ECAT) sample (designated as ECAT-A), the details of which are shown inExample 1.

Example 11 shows a similar comparison of a second ECAT sample(designated as ECAT-B), with the details of this second ECAT samplebeing is shown as Example 10. As can be seen in Table 1B, ECAT-Bincludes both Mg and Ce, which are indicators of sorbent material, suchas that used for reducing sulfur oxides from the flue gases of an FCCprocess. As indicated by comparing Example 11 with the data ofun-treated Example 10, the reduction in the amount of Ce shows that thecurrent process is capable of removing RE materials from asorbent-containing material.

Examples 13-18 show a similar comparison to a third ECAT sample(designated as ECAT-C), with the details of this third ECAT sample beingshown as Example 12.

Example 19 shows results from a rare earth containing ECAT sample thatwas subject to reaction with a 16 molar solution of nitric acid.Following the reaction, the powder and liquid were separated byfiltration. The filtrate was then reacted with a fresh sample of rareearth containing ECAT and the process repeated for a total of 5 cycles.The data in Tables 1A-C is of the rare earth containing sample followingthe 5 cycles.

Similarly, Example 21 in Tables 1A-C show the results obtained after thesecond cycle using hydrochloric acid. The first cycle data is shown inExample 20.

Example 23 shows the effect of adding rare earth compounds back to thesample of Example 22. This experiment was performed by impregnating adilute lanthanum nitrate solution onto the sample of Example 22 in whichthe majority of the rare earth had been removed by the extractionprocess of the present invention. Table 1B shows that the La₂O₃ contentof Example 23 is about the same as that of the initial starting material(Example 12).

For all examples in Examples 1-23 in which the optional heating step ofFIG. 1 is utilized, the heat was applied via Step S2* (i.e., after theRE containing material had been combined with the extracting agent).Examples 24-28 show the effect of applying heat of FIG. 1, during StepS1A* (to the RE containing material) in Example 26, during Step S1B* (tothe extracting agent) in Example 24 and during a combination of bothStep S1A* and Step S1B* for Examples 27-28. The reuse feature of theLa-containing solution, path 80 in FIG. 1, is also shown in that thedata in Examples 24, 25, 26 and 28, which were all taken following threecycles. Example 27 shows the results of Example 28 following just asingle cycle.

Examples 30 and 31 show results of the inventive process on a fresh FCCcatalyst shown in Example 29. Under similar conditions to thoseperformed on ECAT A, ECAT B and ECAT C, the rare earth content wasreduced, but a significantly higher Al₂O₃ loss was observed.

As can be seen from a review of Tables 1A-1C, embodiments of the presentprocesses are capable of extracting a relatively large proportion of therare earth element, or elements (as the oxide equivalent(s)) from the REcontaining material, while extracting only a relatively moderateproportion of the aluminum. Such a result has many benefits, one ofwhich is that with little or no aluminum removal, the support structureof the catalyst remains strong, in embodiments such as those with azeolite structure. Additionally, with the aluminum remaining in the REcontaining material, as opposed to being a separate solid in the liquidsolution, filtration to separate the solids from the liquids, if used,can be accomplished much easier.

As a way of quantify some of these findings, which show a relativelyhigh amount of rare earth extraction, but with a relatively low amountaluminum extraction, Applicant has determined that when the followingrelationships are satisfied, the process is being run as intended:

(i) R_(F)% is less than or equal to approximately 0.4 R_(O)%; and

(ii) A_(F)% is greater than or equal to approximately 0.5 A_(O)%,

where:

-   -   A_(O)% is the original weight percentage of aluminum, as its        oxide equivalent, of the RE containing material before        undergoing the process;    -   R_(O)% is the original weight percentage of the at least one        rare earth element, as its oxide equivalent of the RE containing        material before undergoing the process;    -   R_(F)% is the final, resulting weight percentage of the at least        one rare earth element, as its oxide equivalent, remaining in        the RE containing material; and    -   A_(F)% is the final, resulting weight percentage of aluminum, as        its oxide equivalent, remaining in the RE containing material.

In certain embodiments, improved results can be realized if thefollowing relationships are satisfied:

(ia) R_(F)% is less than or equal to approximately 0.3 R_(O)%; and

(iia) A_(F)% is greater than or equal to approximately 0.7 A_(O)%.

Finally, even further improved results can be achieved if the followingrelationships are satisfied:

(ib) R_(F)% is less than or equal to approximately 0.3 R_(O)%; and

(iib) A_(F)% is greater than or equal to approximately 0.9 A_(O)%.

Another way to quantify some of these findings uses the followingvariables:

W_(RE)=the weight the rare earth containing material, in grams (such asin column 6 of Table 1A);

A_(O)%=the original weight percentage of the aluminum in the rare earthcontaining material, represented as its weight percent oxide equivalentAl₂O₃ (such as in column 5 of Table 1B for Examples 1, 10, 12 and 29);

R_(O)%=the original weight percentage of the at least one rare earthelement, represented as its weight percent oxide equivalent (such as inany of columns 7, 8, 9 or 10 of Table 1B for Examples 1, 10, 12 and 29);

V_(S)=the volume of the solution that the rare earth containing materialis reacted with (such as in column 7 of Table 1A);

R_(F)%=the resulting weight percentage of the at least one rare earthelement, as its oxide equivalent, remaining in the rare earth containingmaterial, after being reacted with the solution (such as in any ofcolumns 7, 8, 9 or 10 of Table 1B for any of the examples other thanExamples 1, 10, 12 and 29 (which relate to the un-reacted catalyst));and

A_(F)%=the resulting weight percentage of aluminum, as its oxideequivalent, remaining in the rare earth containing material, after beingreacted with the solution (such as in column 5 of Table 1B for any ofthe examples other than Examples 1, 10, 12 and 29 (which relate to theun-reacted catalyst));

Where the following relationships are satisfied:

$x = {\frac{R_{o}}{A_{o}} \times \frac{A_{f} - A_{o}}{R_{f} - R_{o}}}$

where x is less than or equal to about 0.8; and

y=W_(RE) (in grams)/V_(S) (in milliliters),

where y is greater than or equal to about 0.025.

In certain embodiments, improved results can be realized when y isgreater than or equal to about 0.03, and even further improved resultscan be realized when y is greater than or equal to about 0.025.

As mentioned earlier, in certain embodiments, the resulting solids thathave undergone the process of FIGS. 1 and 2 could actually perform theirdesignated catalytic functions better than even the original, freshcatalyst, either with or without adding the rare earth materials to themolecular sieve. For example, the following chart of Table 2 shows theresults of catalytic testing over a typical FCC feed on ECAT sampleswith no treatment (Example 12), and with treatment using nitric acid(Example 17) or hydrochloric acid (Example 22) as the extractant, whereExamples 12, 17 and 22 are the same examples of Tables 1A-1C. Theextraction process of the present invention improved performancevariables, such as conversion, LPG, Gasoline and LCO for the 7.0catalyst/oil ratio data shown. In one example (Example 23), the initialrare earth concentration was added back to the extracted ECAT sample andthe sample was again analyzed for catalytic performance. Improvements inperformance remained even after re-applying the rare earth compound backto the catalyst (in this case Lanthanum nitrate).

TABLE 2 Example No. 12, RE-C 17 22 23 Conversion, w % 73.2 77.7 73.875.8 Coke 9.7 11.0 9.6 9.1 C2- 2.78 3.18 2.81 2.76 Total C3s 5.6 7.2 6.26.8 Total C4s 9.9 12.3 10.9 11.8 LPG 15.5 19.6 17.1 18.5 Total Gasoline(C5-430 F.) 45.2 44.0 44.3 45.4 LCO (430-650 F.) 15.7 13.3 14.8 14.1Bottoms (650 F.+) 11.1 9.0 11.4 10.1

Catalytic testing was performed on an ACE Model R+ (Kayser TechnologyInc.) laboratory fluidized bed cracking unit at a catalyst/oil ratio of7.0. The feed properties were API: 20.84; Concarbon: 1.23%, Sulfur:1.52%, IBP: 599F, FBP: 1124F. Liquid and gaseous products were analyzedusing GC methods.

TABLE 3 Particle Size, % Zeolite Surface Example No Reagent <20 umChange Area m2/g  1, RE-A — 0  0% 123  2 Nitric Acid 1 32% 163  3Ammonium Citrate 6  7% 135  4 Nitric Acid 3 26% 125  5 Nitric Acid 0 38%115  6 Sulfuric Acid 9 −32%   58  7 Hydrochloric Acid 0 36% 136  8Acetic Acid 7 −8% 127  9 Nitric Acid 4 22% 128 10, RE-B — 2  0% 11Nitric Acid 5 136 12, RE-C — 6  0% 101 13 Nitric Acid 31  146%  — 14Nitric Acid 31  67% 150 16 Hydrochloric Acid 5 77% — 17 Nitric Acid 694% — 18 Hydrochloric Acid 55  26% — 22 Hydrochloric Acid 5 77% — 23Hydrochloric Acid 70% — 29, RE-D — 11   0% 293 30 Nitric Acid 2 −100% 247 31 Nitric Acid 5 −100%  —

Table 3, above, shows the particle size fraction less than 20 micronsobtained via laser light scattering techniques (Beckman Coulter LS130).Generally, samples which have a high loss in alumina during theprocessing also have an increased amount of <20 micron fraction of theresulting material.

Applicant has also discovered that the amount of zeolite contained inzeolite-containing rare earth containing materials increases by contactwith the reagents of the present invention. Table 3 shows the percentzeolite change, which was measured via x-ray diffraction. The data wasobtained by measuring the intensity of zeolite contained in both theinitial rare earth containing material as well as the rare earthextracted sample following calcination of both to 538-732 C. A positivenumber for zeolite change represents an increase in zeolite content,while a negative represents a decrease. The surface area, as measured bya multi-point BET method (Quantachrome NOVA 3000) on select samples, isgenerally supportive of the zeolite content changes, but is not asprecise due to it being an indirect measurement of zeolite content whencompared with x-ray diffraction.

Thus, as various different embodiments of the present invention havebeen described, it should be clear that various methods are provided forextracting rare earth materials from a rare earth containing material byusing an extracting agent to extract a relatively large proportion ofthe rare earth element(s) from the rare earth containing material. Inpreferred embodiments, the rare earth containing material also containsaluminum, and only a relatively moderate proportion of the aluminum isextracted. The valuable rare earth materials can be extracted from, forexample, spent catalyst, prior to disposing of the spent catalyst, whichresults in both environmental and economic benefits. In otherembodiments, the spent catalyst that has undergone the present processcan be re-used as a catalyst, either with or without additionalmaterials being added thereto. Such re-use of the catalyst providesenvironmental benefits by eliminating the amount of catalyst that endsup in landfills.

While various embodiments of the present invention have been shown anddescribed, it should be understood that other modifications,substitutions and alternatives may be apparent to one of ordinary skillin the art. Such modifications, substitutions and alternatives can bemade without departing from the spirit and scope of the invention, whichshould be determined from the appended claims.

Various features of the invention are set forth in the appended claims.

1. A method of producing a resulting solution including at least onerare earth element, the method comprising the steps of: providing afirst sample of a rare earth containing material having the at least onerare earth element therein; reacting the first sample of the rare earthcontaining material with an extracting agent to extract at least aportion of the at least one rare earth element from the first sample ofthe rare earth containing material; separating the reacted first sample,from which has been extracted at least some of the at least one rareearth element previously associated therewith, from the extractingagent; repeating the reacting step for multiple iterations, designatedas (n) iterations where (n) is a whole number, with an extracting agentthat includes at least some of the rare earth element, but with a sampleof a rare earth containing material that differs from the first sampleof the rare earth containing material, for at least some of saidmultiple iterations of said reacting step, to further enrich the amountof the at least one rare earth element in the resulting solution;repeating the separating step for (n) iterations; and obtaining theresulting solution, which includes the at least one rare earth elementextracted from the rare earth containing material during the multipleiterations of said reacting step.
 2. The method according to claim 1,wherein at least some of the samples of rare earth containing materialused during the multiple iterations of the reacting step include thesame rare earth element as the first sample of the rare earth containingmaterial.
 3. The method according to claim 1, wherein the extractingagent used in at least one of the multiple iterations of said reactingstep is the extracting agent previously used in an earlier iteration ofthe reacting step.
 4. The method according to claim 1, wherein: theextracting agent is a liquid solution having a pH of either less thanapproximately 6 or greater than approximately 8; and the rare earthcontaining material is a molecular sieve containing material.
 5. Themethod according to claim 1, wherein: the extracting agent is a liquidsolution having a pH of either less than approximately 3 or greater thanapproximately 10; and the rare earth containing material is a molecularsieve containing material.
 6. The method according to claim 4, whereinduring each successive iteration of the reacting step, the amount of therare earth element in the extracting agent used during a particulariteration of the reacting step is greater than or approximately equal tothe amount of rare earth element in the extracting agent of theimmediately preceding iteration of the reacting step.
 7. The methodaccording to claim 1, wherein: the at least one rare earth elementcomprises lanthanum (La); the extracting agent includes nitric acid(NO₃); and the resulting solution includes La (NO₃)₃ and (H₂O).
 8. Themethod according to claim 1, wherein: the at least one rare earthelement comprises lanthanum (La); the extracting agent includeshydrochloric acid (HCl).
 9. The method according to claim 1, wherein theextracting agent is a basic solution.
 10. The method according to claim1, wherein the extracting agent is an acidic solution.
 11. The methodaccording to claim 4, wherein at least 10 grams of the rare earthcontaining material are provided for each 100 milliliters of theextracting agent.
 12. The method according to claim 4, wherein themolecular sieve containing material is a fluid catalytic cracking (FCC)catalyst.
 13. The method according to claim 1, wherein (n) is greaterthan or equal to
 200. 14. The method according to claim 1, wherein saidresulting solution, after performing said reacting step multiple times,includes at least 20%, on an oxide basis, of the at least one rare earthelement that was extracted from the rare earth containing material. 15.The method according to claim 4, further comprising the step of rinsingthe reacted molecular sieve containing material with a rinsing liquidbetween at least some of the iterations of said reacting step.
 16. Themethod according to claim 4, further comprising the application of heatduring at least some of said iterations of said reacting step.
 17. Amethod of recovering one or more rare earth elements from a rare earthcontaining material, wherein said method comprises the steps of:providing the rare earth containing material having aluminum and atleast one rare earth element therein, wherein the weight percentage ofthe aluminum, as its oxide equivalent, is defined as A_(O)% and theweight percentage of the at least one rare earth element, as its oxideequivalent, is defined as R_(O)%; and reacting the rare earth containingmaterial with a solution to extract a relatively large proportion of atleast a portion of the at least one rare earth element from the rareearth containing material, while extracting only a relatively moderateproportion of the aluminum, such that the resulting weight percentage ofthe at least one rare earth element, as its oxide equivalent, remainingin the rare earth containing material, defined as R_(F)%, and theresulting weight percentage of aluminum, as its oxide equivalent,remaining in the rare earth containing material, defined as A_(F)%,satisfy the following relationships: R_(F)% is less than or equal toapproximately 0.4 R_(O)%; and A_(F)% is greater than or equal toapproximately 0.5 A_(O)%.
 18. The method according to claim 17, whereinthe following relationships are satisfied: R_(F)% is less than or equalto approximately 0.3 R_(O)%; and A_(F)% is greater than or equal toapproximately 0.7 A_(O)%.
 19. The method according to claim 17, whereinthe following relationships are satisfied: R_(F)% is less than or equalto approximately 0.3 R_(O)%; and A_(F)% is greater than or equal toapproximately 0.9 A_(O)%.
 20. The method according to claim 17, wherein:the solution is a liquid solution having a pH of either less thanapproximately 6 or greater than approximately 8; and the rare earthcontaining material is a molecular sieve containing material.
 21. Themethod according to claim 20, wherein the molecular sieve containingmaterial is a zeolite containing material.
 22. The method according toclaim 17, wherein the at least one rare earth element compriseslanthanum and/or a compound including lanthanum.
 23. The methodaccording to claim 17, wherein the at least one rare earth element isselected from the group consisting of cerium, praseodymium, neodymium,and alloys thereof.
 24. A method of recovering one or more rare earthelements from a rare earth containing material, wherein said methodcomprises the steps of: providing the rare earth containing material, ofa weight W_(RE), having aluminum and at least one rare earth elementtherein, wherein the weight percentage of the aluminum, represented asits weight percent oxide equivalent Al₂O₃, is defined as A_(O)% and theweight percentage of the at least one rare earth element, represented asits weight percent oxide equivalent, is defined as R_(O)%; and reactingthe rare earth containing material with a solution, of a volume V_(S),to extract a majority of the at least one rare earth element from therare earth containing material, while extracting no more than half ofthe aluminum, such that the resulting weight percentage of the at leastone rare earth element, as its oxide equivalent, remaining in the rareearth containing material, defined as R_(f)%, and the resulting weightpercentage of aluminum, as its oxide equivalent, remaining in the rareearth containing material, defined as A_(f)%, satisfy the followingrelationships:$x = {\frac{R_{o}}{A_{o}} \times \frac{A_{f} - A_{o}}{R_{f} - R_{o}}}$where x is less than or equal to about 0.8; and y=W_(RE) (ingrams)/V_(S) (in milliliters), where y is greater than or equal to about0.025.
 25. The method according to claim 24, further comprising a stepof heating the solution, which is in the form of a slurry, during thereacting step.
 26. The method according to claim 25, wherein the heatingstep results in increasing the temperature of the solution to a maximumtemperature within the range of at least approximately 45° C. andapproximately 130° C.
 27. The method according to claim 24, furthercomprising a step of heating at least one of the rare earth containingmaterial and/or the solution prior to the reacting step.
 28. The methodaccording to claim 24, wherein the rare earth containing material is azeolite containing material.
 29. The method according to claim 24,wherein the rare earth containing material is a spent FCC catalyst. 30.The method according to claim 24, wherein the rare earth containingmaterial is a sorbent containing material.
 31. The method according toclaim 1, wherein the extracting agent is a solution selected from thegroup consisting of ammonium citrate, ammonium hydroxide, ammoniumchloride, and ammonium sulfate.
 32. The method according to claim 1,wherein the extracting agent includes an acid selected from the groupconsisting of: maleic acid, formic acid, sulfuric acid, hydrochloricacid, and acetic acid.
 33. The method according to claim 1, wherein theextracting agent is a solution that includes nitric acid.
 34. The methodaccording to claim 4, wherein the molecular sieve containing material isa zeolite containing material, and further wherein the zeolitecontaining material includes at least one element selected from thefollowing: silicon, phosphorus and aluminum.
 35. The method according toclaim 4, wherein the molecular sieve containing material is a fluidcatalytic cracking (FCC) catalyst, and further wherein the FCC catalystis a spent FCC catalyst.
 36. The method according to claim 1, wherein(n) is greater than or equal to
 2. 37. The method according to claim 17,wherein the rare earth containing material is a fluid catalytic cracking(FCC) catalyst, and further wherein the FCC catalyst is a spent FCCcatalyst.
 38. The method according to claim 24, wherein: the solution isa liquid solution having a pH of either less than approximately 6 orgreater than approximately 8; the rare earth containing material is amolecular sieve containing material, wherein the molecular sievecontaining material is a zeolite containing material, and furtherwherein the zeolite includes at least one element selected from thegroup consisting of: silicon, phosphorus and aluminum.
 39. The methodaccording to claim 24, wherein the at least one rare earth elementcomprises lanthanum and/or a compound including lanthanum.
 40. Themethod according to claim 24, wherein the at least one rare earthelement is selected from the group consisting of: cerium, praseodymium,neodymium, and alloys thereof.
 41. The method according to claim 1,wherein the rare earth containing material is a sorbent containingmaterial.
 42. The method according to claim 17, wherein the rare earthcontaining material is a sorbent containing material.